Water Jet Cutting v EDM Cutting

For any business with parts that require cutting, the choice can seem somewhat overwhelming. There are different technologies, each will appear to have pros and cons, which one is best for your job?

We have compared water jet cutting and laser cutting on this site, outlining the different occasions when each might be the best choice, as well as when you would be well advised to get a quote from both and compare.

What though of EDM cutting, a technology that leaves many confused.

What is EDM Cutting?

To give the full name, electrical discharge machining (EDM) is a cutting process where the desired shape is created by electrical discharge. It can also be known through colloquial names such as spark machining, spark eroding, die sinking, wire burning and wire erosion.

Thermal energy is used to remove material from the object in question – it is considered a non-traditional cutting force as it does not rely on direct force.

To quote from a wonderful source, the Encyclopedia Britannia, EDM “involves the direction of high-frequency electrical spark discharges from a graphite or soft metal tool, which serves as an electrode, to disintegrate electrically conductive materials such as hardened steel or carbide.”

Or, in other words, electrodes are used to remove as required from a conductive material.

It is a process that will only work for conductive materials, obviously, this includes metals.

What is water jet cutting?

We assume everyone coming to this site knows what water jet cutting is, but just in case!

Water jet cutting is a process whereby a high-pressure water jet is mixed with an abrasive garnet to create a compelling cutting force.

The process is perhaps best described as accelerated erosion. Modern versions of water jet cutting such as XD technology have taken the process to far greater degrees of accuracy, for instance, the ability to cut complex three-dimensional parts in one fluid motion.

As with EDM, there are some materials that water jet cutting cannot cut – for water jet cutting this is a limited range, including diamond and tempered glass.

Materials That Can Be Cut

Water jet cutting has the edge as there are very few materials that cannot be cut by water jet. Diamond, tempered glass and not much else.

EDM is suitable only for materials that are conductive. For other materials, you will need to consider another option, whether that is water jet, laser or other.

Depth of cut

Water jet and EDM technologies can both cut to a good depth. For EDM, the depth is typically up to around 20cm, while for water jet cutting the depth is at least 25cm in materials.

Often, both will be able to cut to the depth required, but for extremely thick material, it may be that only water jet cutting is suitable.

Speed of Cut

Speed of cut will of course vary depending on the nature of the specific job, but water jet cutting is typically far faster.

Why does this matter, after all a job is likely to have a turnaround time of a few days, what difference does the duration of the actual cut make?

It matters because speed – as long as that speed does not impact accuracy – keeps costs down and makes the process more efficient. It also means that the cutting machine can work through more jobs per hour, each individual job, therefore, monopolising the machine for far less time.

The old saying time is money is very true in this instance.

Where EDM can be more competitive is when parts can be stacked, for instance, if the exact same cut was required to be made multiple times, layers of thin material could be stacked and the same cut made through them all. However, even in this instance, it is likely to be far slower than water jet cutting would be.

Accuracy

While water jet cutting is faster and therefore often more economical, EDM prides itself on being more accurate.

What does accuracy mean in this instance? It refers to the degree of accuracy in corners and other intricate cuts. Because water jet cutting relies on the physical process of water and abrasive making the cut, there is always a tiny margin for error.

The difference is rarely visible to the naked eye – water jet cutting is of an accuracy that sees it used to make logos out of ceramic tiles, and artwork for world-leading exhibitions.

However, it is only fair to mention that EDM does hold a small advantage in this category that will be relevant in some jobs.

EDM can, in some instances, struggle to produce sharp corners.

Making Complex Parts

Both water jet cutting and EDM are capable of making complex, intricate three-dimensional parts.

For water jet cutting, XD cutting heads enable this – this technology that moves the cutting head through multiple axis, all controlled by software.

EDM also uses software to create intricate designs in the conductive materials it is able to cut.

Cost

When both options are suitable, water jet cutting will typically be more cost-effective. It is, in some ways, a wonderfully basic yet effective technology – simply using the power of water and naturally occurring abrasive to cut efficiently.

However, EDM is a superb technology in its own right and it is often worth getting quotes from different technologies to compare and contrast.

Next steps.

AT TMC waterjet, the UK’s leading experts on water jet cutting we are always happy to offer advice.

Is water jet cutting the most suitable technology for your job? Contact us and we will discuss your requirements and provide an obligation free quote.

Work with the UK’s leading Water Jet Cutters

At TMC, we are a water jet cutter who serve the whole of the UK and increasingly Europe too, with clients across the content trusting us to work on their projects.

Despite our success, we remain a company that focusses on every client and work on projects of all sizes.

If you think water jet cutting might be of use for your project, please do get in touch for an obligation-free chat.

Call us on 01625 610 441 or use our Contact Form.